J Korean Ophthalmol Soc.  2019 May;60(5):407-413. 10.3341/jkos.2019.60.5.407.

Dry Eye Syndrome after Refractive Surgery: Comparative Outcomes of SMILE and LASIK

  • 1Department of Ophthalmology, SahmYook Medical Center, Seoul, Korea.
  • 2Saevit Eye Hospital, Goyang, Korea. eyekun@gmail.com


To determine possible differences in dry eye syndrome in relation to surgery methods, especially between small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK), in Korean patients.
This study involved 20 patients (20 eyes) who were treated with SMILE surgery and 23 patients (23 eyes) who were treated with FS-LASIK. The Schirmer test, tear film breakup time (TBUT), corneal staining score (CSS), and measurement of changes in the lipid layer thicknesses at one week, and 1 and 3 months after surgery were performed. Possible correlations between indicators of dry eye syndrome were then analyzed.
There was a significant time difference in some indices. The TBUT was 5.52 ± 1.50 s after one week for SMILE patients and 4.59 ± 2.50 s for FS-LASIK patients (p = 0.02). The CSS was 0.50 ± 0.51 after 1 week for SMILE patients and 1.14 ± 0.99 after 1 week for FS-LASIK patients (p = 0.04). The CSS was 0.50 ± 0.51 after 1 month for SMILE patients and 1.10 ± 0.93 after 1 month for FS-LASIK patients (p = 0.03). Three months later, the CSS was 0.39 ± 0.50 for SMILE patients and 0.94 ± 0.85 for FS-LASIK patients (p = 0.03). However, the Schirmer test did not show a significant difference postoperatively for SMILE and FS-LASIK patients at 1 week (p = 0.44), 1 month (p = 0.68), and 3 months (p = 0.23). Additionally, the thickness of the tear film lipid layer did not show a significant difference during the same periods (p = 0.36, p = 0.43, and p = 0.72, respectively).
When compared with FS-LASIK surgery, SMILE surgery resulted in significantly improved test results in the TBUT and CSS for dry eye syndrome.


Dry eye syndrome; Lipiview; keratomileusis; Laser in situ (LASIK); Small incision lenticule extraction (SMILE)

MeSH Terms

Dry Eye Syndromes*
Keratomileusis, Laser In Situ*
Refractive Surgical Procedures*


  • Figure 1 Ocular surface parameters after SMILE and FS-LASIK. Ocular surface parameters including Schirmer test, tear break-up time, corneal staining score, lipid layer thickness were compared between patients undergoing SMILE and FS-LASIK. SMILE = small incision lenticule extraction; FS-LASIK = femtosecond laser assisted in situ keratomileusis. *p < 0.05 in SMILE, **p < 0.05 in FS-LASIK.


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